Just 30 minutes of nature a week could reduce your risk of depression

Shutterstock Just 30 minutes a week spent outdoors — whether you're visiting the park, hiking, or exploring new tracks with your dog — is enough to lower your risk of developing high blood pressure and depression, a new study has found.

Australian researchers also found that city residents who made an effort to spend time in a 'green space' once a week were more comfortable being in social situations, so it really is time to shut your computer and get some air.

Shanahan and her team analyzed data from 1,538 residents of the city of Brisbane, Queensland, who were asked about their weekly habits when it came to nature and physical activity, and assessed on their mental and physical health.

The participants' experiences of nature were measured by three factors: the average frequency of visits to outdoor 'green spaces' during a year; the average duration of visits to these spaces across a week; and the intensity of nature in these spaces — measured by the amount and complexity of greenery in that space.

Health risks for the group were established using a standardized test that identifies mild or worse depression, anxiety or stress, and recording who's undergone treatment for high blood pressure.

An individual's perception of social cohesion — which means a willingness to cooperate with others in a social situation - was assessed via responses to a survey that measures things like trust, reciprocal exchange within communities, and general community cohesion.

The team found that people who made regular long visits to green spaces had lower rates of depression and high blood pressure, and those who visited more frequently had greater social cohesion.

"Higher levels of physical activity were linked to both duration and frequency of green space visits," they conclude in the journal Scientific Reports. "A dose-response analysis for depression and high blood pressure suggest that visits to outdoor green spaces of 30 minutes or more during the course of a week could reduce the population prevalence of these illnesses by up to 7 percent and 9 percent respectively."

There are, of course, limitations in this research, the biggest two being that the participants self-reported their outdoor activity, so the results could be slightly skewed, and that the researchers can only show a correlation between exposure to nature and health benefits — they have not examined the biological changes going on inside the participants that could explain this link.

Back in July 2015, a similar study found that a 90-minute walk through a grassland area actually altered the participants' neural activity in relation to 'rumination' — repetitive thoughts focused on negative aspects of the self that can lead to an increased risk of depression.

"By performing brain scans on the walkers before and after the expedition, the team found that neural activity in the subgenual prefrontal cortex — the area of the brain that's active during rumination — had decreased in the volunteers who explored the natural environment. Their experience was consistent with this finding, with the group reporting that they found themselves ruminating less during the walk."

Another study from earlier this year found that simply taking a walk down a tree-lined street — even in an urban setting — could significantly lower stress levels, with volunteers exposed to nature showing they were better able to keep their cool when faced with some truly horrifying experiences, like preparing to deliver a speech, and performing a subtraction test in front of judges.